According to the Washington Post, Democrats are continuing to push for an increase in marginal rates, but only on the very rich.

A faction of congressional Democrats is making a push to persuade President Obama to consider a compromise on tax policy that would leave only the nation’s 315,000 richest households facing higher taxes in January.

That’s because these Democrats still think that under the current tax code they will be able to raise more revenue by letting marginal rates go up. But that ignores the fact that the federal government has never been able to get much more than 19 percent of GDP in tax revenues, and sustain that level for very long, no matter how high the top marginal tax rate goes. Consider this chart:

It shows the historical path of federal taxation as a percentage of GDP (using the earliest records available from the OMB) alongside top-marginal-tax-rate data from the Tax Policy Center. From 1930 to 2010, tax-revenue collection in the United States has never topped 20.9 percent, averaging 16.5 percent of GDP over 80 years. This despite the drastic historical fluctuation in tax rates on the wealthiest Americans.

This reality is called Hauser’s Law, after Standford University professor Kurt Hauser, who had a very good piece in the Wall Street Journal this weekend: